The preparation of coloured cheeses originated in Somerset, Southern England in a place called Cheddar. It was here, noted during the summer months in the Middle Ages, that the natural carotene colour in the milk was carried through to the cheese curd and resulted in the preparation of the traditional coloured cheddar cheese. The visual aspect of the colour became extremely important in terms of consumer perception of the quality of cheddar cheese. Thus, today, when milk is pasteurised, the use of annatto colour is extremely important to achieve the visual appearance of coloured cheese, including cheddar, Leicester, Gloucester, etc. The orange-yellow colour derived from annatto is synonymous with cheddar cheese.
During the cheese-making process, coagulation of milk yields solid curds (later to become the cheese portion) and a watery portion, commonly referred to as fluid whey. Fluid whey generally contains 5-7% solids, mainly fats, soluble and insoluble proteins, carbohydrates and ash, the remaining portion being mainly water. Fluid whey has a very high biological oxygen demand (BOD). As such, disposal of fluid whey by application to land or watercourses is typically illegal in most civilized countries. Treatment in an effluent plant is expensive. Traditionally, fluid whey has been supplied as an animal feed, mainly to pigs. These factors have resulted in development of processing technologies to recover the valuable components of the whey fluid for preparation of high value-added food and feed ingredients for the world-wide food and feed industry, e.g. whey protein and its derivatives are now being processed to high value added proteins for the baby food, functional food, and prepared food markets. Whey cream is processed into valuable milk fat products.
However, the use of annatto to produce cheddar cheese, for example, also causes colouring of the whey by-product stream in cheese processing and this colouring of the whey stream causes major loss of value and inefficiencies in large dairy whey processing plants. There are processes for bleaching the annatto colour from the whey fraction but these processes may add extra processing steps, may alter the nature, composition and functionality of the resulting whey by-products and the uses for the bleached whey by-product may be legally restricted in the market.
For example, the various methods used for bleaching the coloured whey by-products include the use of hydrogen peroxide, benzyl peroxide, etc., which have the disadvantage in that the protein composition of the whey by-product is inherently changed. As such, the consequences of the bleaching process on the attributes of the protein composition of the whey by-product are undesirable for whey processing.
Some processes have been devised to avoid bleaching the coloured whey by-product. For example, U.S. Pat. No. 6,120,820 to Brody et al. uses a separation technology in an effort to remove the colour from the coloured whey by-product stream. This process attempts to separate the highly coloured fraction from the less coloured fraction in the whey by-product stream after pitching. By its nature, this approach adds additional processing steps and is inherently a more costly process. More importantly, the process is not 100% efficient in removing the colour from the already coloured whey by-product stream.
Another attempt to deal with the problems associated with annatto-coloured whey by-product is described in GB 2,248,170 to F. Hoffmann La-Roche AG. The solution proposed in GB 2,248,170 is the use of synthetic beta-carotene, which is produced by chemical processing technologies and identical to naturally occurring beta-carotene, in place of annatto. However, when synthetic beta-carotene is used, the colour shade of the resultant cheddar cheese is visually different from the cheese coloured with annatto. As annatto is the industry standard of colour in cheddar cheese, the yellow colour produced by synthetic beta-carotene is not desirable.
Furthermore, the colourant described in GB 2,248,170 also includes gelatin and a preservative in the formulation. As gelatin is sourced from the bones of animals such as pigs and the like, it may be considered undesirable in the manufacture of cheese, and particularly in the manufacture of cheese geared towards the vegetarian market. Furthermore, the use of a preservative may have a negative effect on starter culture growth, which is a necessary part of cheese making. Any ingredient that may have a deleterious affect on the starter culture vitality should ideally be avoided. As such, the formulation provided therein may have an adverse effect on the finished cheese product. Thus, there is a necessity to provide a colouring composition that prevents colouration of the whey by-product stream, while simultaneously providing a finished cheese product with the same colour as annatto-coloured cheeses.